The program was designed to extract secrets from "high value" suspects during the years after the Sept. 11, 2001, terrorism attacks on the United States.

Blindfolded, hooded and wearing earmuffs, suspects were shackled and flown to secret interrogation centers. The buildings were quiet, clinical and designed to fill prisoners with dread. Detainees were shaved, stripped and photographed nude.

When the CIA interrogator removed the hood, the questioning began. Whenever the prisoner resisted, the documents outlined a series of techniques the CIA could use to bring him back in line:

• Slapping prisoners on the face or abdomen was allowed. So was grabbing them forcefully by the collar or slamming them into a false wall.

• Water hoses were used to douse the prisoners for minutes at a time.

• Prisoners were put into "stress positions," such as sitting on the floor with legs out straight and arms raised to cause discomfort.

Some of the techniques, such as stripping a detainee naked, depriving him of sleep and putting a hood over his head, are prohibited under the U.S. Army Field Manual. But in 2002, the Justice Department authorized CIA interrogators to step up the pressure even further on suspected terrorist Abu Zubaydah.

Justice Department lawyers said the CIA could place Zubaydah in a cramped confinement box. Because Zubaydah appeared afraid of insects, they also authorized interrogators to place him in a box and fill it with caterpillars (that tactic ultimately was not used).

Finally, the Justice Department authorized interrogators to use waterboarding, a technique in which Zubaydah was strapped to a board, his feet raised above his head. His face was covered with a wet cloth as interrogators poured water over it. The United States now considers waterboarding a form of torture.